EDITORS' SUGGESTION
The cocktail party effect refers to the brain’s ability to focus on a single auditory stimulus amidst the cacophony of background noise. This selective attention also resonates in electromagnetic telecommunication, where the surge in wireless communication exacerbates signal interference. To address that issue, researchers have developed reconfigurable intelligent surfaces, mirrors that dynamically shape their reflectivity to enhance wireless performance. Drawing inspiration from these advancements, the authors propose to extend this concept to the acoustic domain, where similar issues of signal clarity and interference persist, but over a much wider frequency range.
Constant Bourdeloux, Mathias Fink, and Fabrice Lemoult
Phys. Rev. Applied 21, 054039 (2024)
EDITORS' SUGGESTION
Using cavity quantum electrodynamics to enhance light-matter interaction has been pursued with increasing efforts to develop miniaturized, stable, and fully integrated systems for quantum networks or secure communication. Hybrid systems combining photonic platforms and quantum systems are a valid option, but accessing individual spin states remains challenging. This work explores the combination of silicon nitride photonics and negatively charged silicon-vacancy centers in nanodiamonds as a spin-photon interface and elaborates on the hybrid system’s performance. The results can be used to benchmark and outline future spin-based quantum photonic devices.
Lukas Antoniuk et al.
Phys. Rev. Applied 21, 054032 (2024)
EDITORS' SUGGESTION
Nanomechanical computers promise robust, low-energy information processing, but generally require electronics to handle bits with different oscillation frequencies, limiting scalability. The authors present an acoustically driven logic gate with a single frequency of operation, with the logic states defined by a nonlinear mechanical resonator, allowing purely mechanical information transfer. Since inputs and output all share the same frequency, they are compatible with cascaded chains of gates. This architecture is CMOS-compatible, and with miniaturization could permit energy efficiency approaching the fundamental Landauer limit.
Erick Romero et al.
Phys. Rev. Applied 21, 054029 (2024)
EDITORS' SUGGESTION
Defective devices can severely impact the performance of hardware-based neural networks, in particular resistive crossbar arrays. This study introduces a network training approach that reduces the influence of defective devices, maintaining inference accuracy. The authors demonstrate this approach on a set of dies each containing a crossbar array consisting of 20,000 magnetic tunnel junction devices. They also develop a generalized approach using the statistics of defects and demonstrate similar performance on all dies. These results translate to a manufacturing setting where millions of dies with possible defects are produced, but the performance of even subpar chips can be guaranteed.
William A. Borders et al.
Phys. Rev. Applied 21, 054028 (2024)
EDITORS' SUGGESTION
Transition-metal dichalcogenides (TMDCs) are promising building blocks for future electronic circuits, but their performance is often hindered by poorly understood electron-phonon interactions. This study leverages a fresh ab initio approach, combining density-functional theory with the linearized Boltzmann transport equation (LBTE) and nonequilibrium Green’s functions (NEGF), to explore phonon-limited transport in TMDCs. The authors find that LBTE and NEGF return very similar mobility values despite the different approximations upon which they rely, thus paving the way for comprehensive device simulations that include electron-phonon scattering.
Jonathan Backman, Youseung Lee, and Mathieu Luisier
Phys. Rev. Applied 21, 054017 (2024)
LETTER
Ramsey interferometry is an important technique in precision spectroscopy and quantum coherence measurement. The authors explore an innovative scheme in which splitter pulses are implemented by geometrical means, eliminating the temporal dependence of the atom-light interaction. This translates to an interferometer that is insensitive to the mean velocity of the atomic ensemble, making it suitable for applications in quantum computing and simulation, as well as atomtronic circuits. Using this geometric Ramsey interferometer, the team measures the phase accumulation during the free-evolution time due to a geometric scalar term.
Chetan Sriram Madasu, Ketan Damji Rathod, Chang Chi Kwong, and David Wilkowski
Phys. Rev. Applied 21, L051001 (2024)
LETTER
Accurate measurement of a material’s coefficient of thermal expansion is a potentially powerful probe for investigating phase transitions. Unfortunately, familiar techniques are either low-resolution or put stringent requirements on sample preparation. This study implements ultrastable optical-fiber interferometry for contactless optical measurement with picometer spatial resolution, and can measure fragile samples less than 100 µm thick with millikelvin-level temperature resolution. Using their method on BaFeAs, the authors discover hysteresis at the first-order phase transition between its antiferromagnetic and paramagnetic phases, with a boundary moving at about 188 µm/s.
Xin Qin et al.
Phys. Rev. Applied 21, L041003 (2024)
PERSPECTIVE
Spin waves and their quanta magnons are the collective excitations of a spin systems of a magnetic material, which offer the potential for higher efficiency and lower energy consumption in solving specific issues in data processing. This Perspective discusses the current challenges in realizing magnonic circuits based on the building blocks developed to date, and further looks at the application of magnons in neuromorphic networks and stochastic, reservoir, and quantum computing, and discusses their advantages over conventional electronics in these areas.
Qi Wang et al.
Phys. Rev. Applied 21, 040503 (2024)
PERSPECTIVE
Dynamic beamforming is critical in applications such as radar detection, holographic imaging, and reconfigurable intelligent surfaces (RIS). This Perspective reviews a revolutionary and economical technique to achieve dynamic beamforming, utilizing the moiré pattern formed by twisted stacked metasurfaces. Research here faces challenges such as far-field calculations and the inverse design of specific radiation patterns, due to our limited understanding of the complex mode coupling between the moiré pattern and the metallic back plate. The authors outline potential solutions and project the future applications and research directions for the reflective moiré metasurface.
Shuo Liu and Tie Jun Cui
Phys. Rev. Applied 21, 040502 (2024)